Experimental Study Of Eardrum Ventilating Tube Prevent And Treat Flight Personnel Eustachian Tube Dysfunction

Background:Pilot's eustachian tube dysfunction and it arouse series diseases perplex aviatic and clinical doctor all along. With high-performance battleplane equip our troops in recent years, the morbidity have be increasing. The resulting nonbattle casualty has seriously affect troops campaign capability. This problem has never been solution very good since aircraft was invented. Although there are "valsava" act and "chewing swallowing" action. However, at flight speeds exceeding the speed of sound today, rapidly changing battlefield environment, pilots in the short time to make a number of operating action, at the same time they need to do this"valsava" act or "swallowing chewing" movements, it is almost impossible. On the one hand spliting-up attention and on the other hand give rise to accident potential for the flight safety.Eardrum ventilating tube provides a new method for the prevention and treatment of pilot's eustachian tube dysfunction. A major role of eardrum ventilating tube is it provide another channel in the middle ear cavity and the outside world. Normal condition, the function of the balance of the middle ear cavity and the outside world atmospheric pressure is to be completed by the eustachian tube. However, when the eustachian tube obstruction occurred due to various reasons, its ventilation function will be lost. Resulting in secretory otitis media or aero-otitis media or alternobaric vertigo and so on problems. Eardrum ventilating tube has effectively solved the problem through inserted snorkel on the tympanic membrane. This method is simple, less damage, the tympanic membrane can be heal in the short time after eardrum ventilating tube was removed. With the ear microsurgery of the rapid development and popularized, This method is likely to become the best way of prevent and treat combat pilots eustachian tube dysfunction.At present, only very few scholars make preliminary exploration in this respect. Dinis discuss detail the main reasons of the aero-otitis media. Include:eustachian tube dysfunction, bacterial infections and immune dysfunction; Can be caused by three separate disease, may also be causes and effects by a common role in the pathogenesis. Xu Xianrong placed the PVC tube in guinea pigs left nasal cavity to nasopharynx 7d, while tubes were place before and after and after cure, guinea pigs were low pressure chamber experiments respectively. Observed changes of eardrum and tympanogram after each low pressure chamber experiments. Results of experiment:changes of eardrum and tympanogram obviously, produced the animal models of eustachian tube dysfunction successfully. These studies confined to etiology of eustachian tube dysfunction or made animal model. On how the prevention and treatment of eustachian tube dysfunction did not involve. So the researches of prevent and treatment of eustachian tube dysfunction is still blank.PurposeIn order to find the methods to prevent and treat aero-otitis media, this experiment stand by Naval General Hospital Research Research Fund, trying to prove that eardrum ventilating tube in the prevention and treatment of eustachian tube dysfunction feasibility by means of animal experiments.Based on the animal model of eustachian tube dysfunction were made successfully, the animals were divided into experimental and contrast groups, were perforated by laser on eardrum respectively. And then enter the low pressure chambers. Simulation fighter flight action, observed congestive situation of eardrum and middle ear mucosa of animals after out of low pressure chambers. To estimate the feasibility that ventilating tube inplant the eardrum to prevent and treat eustachian tube dysfunction.Methods:1.Experimental animals:Experimental animals were clean versicolor 30 guinea pigs, Male or female no limitative, Preyer's reflex normal,600-700 grams of body mass, by the Navy General Hospital, Center for Laboratory Animal[Animal Center, Permit No. SYXK(军)2007-014]; Guinea pig rearing environment:Room temperature 18-26℃Humidity45-65%.Free eating and drinking.2.Animal anesthesia:Anesthesia in the PLA Naval General Hospital, the Central Laboratory of Otolaryngology; 1ml/kg dose by intramuscular injection Sumianxin II.3. Animal model:3.1 Examine by electricity otoscopy after anesthesia excellence, excluded from disorders of the external ear and middle ear; Tympanogram (GSI33 type) inspection, confirmed the good bilateral eustachian tube function. After passing a medical examination,guinea pigs were randomly divided into A, B, C three groups,10 in each group.3.2 A group was the experimental group. Under the guidance of nasal endoscope. Bilateral PVC pipe inserted into the nasal cavity to the nasopharynx, to made inflammatory response of congestion and edema in nasopharyngeal mucosa. Three days later, another tympanogram check, double ears are B-type curve,proved the animal model of bilateral eustachian tube dysfunction were made successfully.3.3 Group B for their own contrast group, PVC pipe were inserted into the left nasal cavity to nasopharynx, to made model of the left eustachian tube dysfunction. No treatment for the right of self-control.After three days check tympanogram again. Left ear was B-type curve.Right ear was the A-type curve, The own contrast group of animal models was prove successful production.3.4 C group was the control group. Bilateral nasopharyngeal not insert PVC pipes.Binaural tympanogram checks are A-type curve.3.5 30 experimental guinea pigs were perforated on the left eardrum using microscope (Carl zeiss S8 type) by laser (Sharplan CO2 laser power 1 W, continuous mode, spot diameter of 0.4mm, focal length 300mm).Perforation diameter was about 1mm, simulation of eardrum ventilating tube.4.Flight Simulator methods:Regained consciousness after anesthesia,30 experimental guinea pigs were placed in low pressure chamber(1978 Shanghai Jiangnan Shipyard Made). 15 m/s up to 5000 meters height, stay five minutes, and then 70 m/s simulated flight movements fell to the ground.5.Results observe:5.1 Observed congestive or exudation situation of eardrum and middle ear mucosa of animals after out of low pressure chambers by electric otoscope. Criteria:0°/Tympanic membrane without change;Ⅰ°:Tympanic membrane malleus handle and the department of relaxation had some mild congestive;Ⅱ°:Tympanic membrane malleus handle and the department of relaxation and peripheral had congestive;Ⅲ°:Tympanic membrane congestive diffuse, even middle ear exudate, hemorrhage or tympanic membrane perforation.5.2 Bilateral tympanograms check-up.Statistics A, B, C curves of the three forms of data.Results:1.A group:Bilateral experimental group.After flight simulator the left 10 ear tympanic membrane were no mucosal hyperemia. The right ear drum 10, in varying degrees of congestive and invagination. Even hemoexudate in middle ear, and have two ears tense of tympanic membrane perforation. 2.B group:Their own contrast group.10 left ear drum and middle ear mucosa no congestive; 10 ears right ear drum has three different degrees of congestive invagination.The remaining seven ear drum checked no abnormal.3.C group:Contrast group,10 left ear drum and middle ear mucosa no congestive; 10 ears right ear drum has four different degrees of congestive invagination.The remaining six ear drum had no abnormal inspection.Conclusions:1.A group of guinea pigs, flight simulation in low pressure chamber, left tympanic membrane to balance the internal and external pressures of middle ear. There is no perforation or congestive occurred; Right ear drum can not balance the internal and external pressures of middle ear,10 ears tympanic membrane varying degrees of congestive and invagination. There are even two ears tense of tympanic membrane perforation.Proved that laser perforation of eardrum simulation eustachian tube can be a very good balance of tympanic membrane changes in internal and external pressures.2.B group of guinea pigs, flight simulation in low pressure chamber, left tympanic membrane to balance the internal and external pressures of middle ear. There is no perforation or congestive occurred; The balance of Internal and external pressures of right ear drum rely on the normal eustachian tube,7 ears normal. The remaining 3 ears were varying degrees of tympanic membrane hyperemia, tympanogram curve B. Are proof that a laser-made hole simulation eustachian tube can be a very good balance of tympanic membrane changes in internal and external pressures.3.C group was the control group. Flight simulation in low pressure chamber, left tympanic membrane to balance the internal and external pressures of middle ear. There is no perforation or congestive occurred; The balance of Internal and external pressures of right ear drum rely on the normal eustachian tube,6 ears normal. The remaining 4 ears were varying degrees of tympanic membrane hyperemia, tympanogram curve B. Further proof that a laser-made hole on eardrum simulation eustachian tube can be a very good methed to balance internal and external pressures of tympanic membrane.